The Pain of Pain: or Patience for Patients

Transcription

1 The pain of pain or: Patience for Patients Alan Bielsky Objectives Discuss mechanisms of acute on chronic pain Explain the practical use of multimodal analgesia Detail different regimens that may benefit the chronic pain patient 1 2 The Problem 35 yo male with chronic lower back pain s/p spinal chord stimulator Obesity and OSA Fibromyalgia Major depressive disorder Presents for Lap Chole The surgeon No regional for Lap Chole! My Lap Chole s don t hurt This patient is going to do fine 3 4 The anesthesiologist Common Theme: Neuroplasticity Lenz M, Höffken O, Stude P, Lissek S, Schwenkreis P, Reinersmann A, Frettlöh J, Richter H, Tegenthoff M, Maier C.: Bilateral somatosensory cortex disinhibition in complex regional pain syndrome type I. Neurology Sep 13;77(11): Epub 2011 Aug

2 Risk factors for severe postoperative pain Preexisting pain Anxiety Age Type of surgery From: Spinal cord mechanisms of pain Br J Anaesth. 2008;101(1):8-16. doi: /bja/aen088 Br J Anaesth The Board of Management and Trustees of the British Journal of Anaesthesia All rights reserved. For IIp et al. Predictors of Postoperative Pain and Analgesic Consumption: A Qualitative Systematic Review. Anesthesiology December Risk factors for opioid abuse Preoperative opioid use Preoperative benzodiazapene use Depression Male Age greater than 50 years Substance abuse history The bad outcome Patient stays past due Patient complains about lack of pain control Patient goes home on unreasonable analgesic regimen 9 10 Let s pivot then Chronic pain. pain intensity is not the best measure of the success of chronic pain treatment. When pain is chronic, its intensity isn't a simple measure of something that can be easily fixed. Multiple measures of the complex causes and consequences of pain are needed to elucidate a person's pain and inform multimodal treatment Balantyne JC, Sullivan MD. NEJM

3 Think about it Neuroplastic changes to somatosensory system Upregulation of opioids and GABA receptors Psychosocial change Intraoperative nerve injury and tissue damage So what do you do? Patience Multimodal analgesia Aggressive regional Patience Patience Avoid worsening the hijacking of the somatosensory system Multimodal Therapy Using multiple methods to achieve highest satisfaction Hit multiple targets Minimize side effects and toxicity Maximize function Opioid reduction to rescue role only Step 1: therapeutic relationship Establish that you are advocating for the patient Set and explain boundries Continue pain meds Expect for plans to change Be patient Set realistic goals of analgesia Most importantly Forget pain scores. They are of no use to you now!!!! Focus on functional pain relief Don t let volume control the amplitude of your reaction Tools! Regional Ketamine Lidocaine Esmolol Other stuff 17 18

4 Aggressive Regional Benefit of regional usually outweighs risks Takes some convincing of surgeons May seem like overkill It isn t Ketamine What is ketamine Phencyclidine anesthetic Dissociative anesthetic How does ketamine work? Reversible antagonism of the N methyl D aspartate receptor 2 4 μ opioid receptors Muscarinic receptors Monoaminergic receptors γ aminobutyric acid receptors Where do we use it? Dose and Effect and effects First given to soldiers in Vietnam Extensive use as an anesthetic agent First line drug in battlefields, underdeveloped countries Typically given IV, but can be given IM/SC and orally. 0.5 mg/kg Anti hyperalgesic 1 mg/kg Anti nociceptive 4 mg/kg Amnestic/Anesthetic 23 24

5 Side effects Sedation Somnolence Dizziness Sensory illusions Hallucinations Nightmares Blurred Vision In whom should we consider subanesthetic ketamine? Patients undergoing painful surgery (grade B recommendation, moderate level of certainty). Opioid dependent or opioid tolerant patients undergoing surgery (grade B recommendation, low level of certainty). Opioid dependent or opioid tolerant patients with acute or chronic sickle cell pain (grade C recommendation, low level of certainty). For patients with sleep apnea, ketamine may be considered as an adjunct to limit opioids (grade C recommendation, low level of certainty). How do you run it Bolus dosing should not exceed 0.35 mg/kg, and infusions for acute pain generally. Infusions generally should not exceed 1 mg/kg/hr, though adverse effects will generally limit infusion rates below 0.5 mg/kg/hr Does the evidence support it? Overall, we conclude that moderate evidence supports use of subanesthetic IV ketamine bolus doses (up to 0.35 mg/kg) and infusions (up to 1 mg/kg per hour) as adjuncts to opioids for perioperative analgesia (grade B recommendation, moderate level of certainty). Are there contraindications? poorly controlled cardiovascular disease pregnancy active psychosis Severe liver disease Caution with moderate liver disease hepatic dysfunction, evidence supports 29 30

6 What about ICP Should be avoided in uncontrolled ICP and IOP Evidence is only C level here Historic usage in polytrauma Practicalities Prone to errors Run in a secure box You don t have to wean it Lidocaine infusions: What is it? Lidocaine Effects come with infusion rates that mimic levels seen with epidural administration Clinical effect (8 hrs) exceeds half life of 1.5 hrs Huh?? Lidocaine: Why? Interferes with pro inflammatory signaling Blocks excitatory responses in wide dynamic range neurons Seems to block the priming of polymorphonuclear granulocytes Unstable coronary disease Recent MI Heart failure Heart block Electrolyte disturbances Liver disease Cardiac arrhythmia disorders Seizure disorders 35 36

7 So what do you do? Toxicity Peripheral to Central Bolus 1 mg/kg Infusion of 2 mg/kg/hr Steady state reached at 8 hours No evidence for use beyond 24 hours At these lower infusion rates, no need to check levels On the floor? Same monitoring as an opioid PCA Nurse education vital Ongoing observation needed Select your own place Esmolol Esmolol? Why Mechanism unclear Thought to be related to voltage gated calcium channels being regulated by beta adrenergic antagonists Might also block hippocampal activation by glutamate receptors Esmolol How Loading dose of 0.5 mg/kg Run from mcg/kg/min Titrate for BP and HR Contraindicated in reactive type lung disease 41 42

8 Does it work? Evidence seems to be in big bowel cases and chest cases Limited data in acute on chronic pain Spine surgery has benefit Hysterectomy and breast surgery have not shown benefit What about what not to do? Things to avoid Remifentanil: Hyperalgesia Discontinuing home meds: Withdrawal Minimizing pain: Why Silver Bullet Theory Thinking outside the box TENS units! Lidoderm patches Massage/acupuncture/healing touch Whatever gets you through the night Back to our patient 35 yo male with chronic lower back pain s/p spinal chord stimulator Obesity and OSA Fibromyalgia Major depressive disorder Presents for Lap Chole Reasonable Things General anesthetic Continue home meds Ketamine infusion x 24 hrs Quadratus Lumborum block PO celecoxib and acetaminophen Postop metaxolone, low dose oxycodone Acupuncture session at POD